National Hellenic Research Foundation

Athens, Greece

National Hellenic Research Foundation

Athens, Greece

The National Hellenic Research Foundation is a historic and scientific research center in Athens, Greece, Wikipedia.

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Chrysina E.D.,National Hellenic Research Foundation
Mini-Reviews in Medicinal Chemistry | Year: 2010

The quest for the discovery of new antihyperglycaemic agents has been more intense the last years due to the rapid increase of mortality associated with type 2 diabetes. Glycogen metabolism has been one of the major causes of the elevated blood glucose levels; hence, special attention has been drawn to the control of the enzymes implicated in the relevant pathway. To this end, the allosteric enzyme of glycogen phosphorylase, has been proposed as molecular target for the design of potential new antidiabetic agents by an interdisciplinary approach comprising organic synthesis, kinetic and X-ray crystallographic studies and physiological experiments. The results derived from the thorough investigation of the catalytic site of the enzyme with the structure-based inhibitor design approach are summarized with emphasis on the most potent inhibitors identified for different classes of compounds. © 2010 Bentham Science Publishers Ltd.

Chatziioannou A.A.,National Hellenic Research Foundation | Moulos P.,National Hellenic Research Foundation
Frontiers in Neuroscience | Year: 2011

StRAnGER is a web application for the automated statistical analysis of annotated gene profiling experiments, exploiting controlled biological vocabularies, like the Gene Ontology or the KEGG pathways terms. Starting from annotated lists of differentially expressed genes and gene enrichment scores, regarding the terms of each vocabulary, StRAnGER repartitions and reorders the initial distribution of terms to define a new distribution of elements. Each element pools terms holding the same enrichment score. The new distribution thus derived, is reordered in a decreasing order to the right, according to the observation score of the elements, while elements with the same score, are sorted again in a decreasing order of their enrichment scores. By applying bootstrapping techniques, a corrected measure of the statistical significance of these elements is derived, which enables the selection of terms mapped to these elements, unambiguously associated with respective significant gene sets. The selected terms are immunized against the bias infiltrating statistical enrichment analyses, producing technically very high statistical scores, due to the finite nature of the data population. Besides their high statistical score, another selection criterion for the terms is the number of their members, something that incurs a biological prioritization in line with a Systems Biology context. The output derived, represents a detailed ranked list of significant terms, which constitute a starting point for further functional analysis. © 2011 Chatziioannou and Moulos.

Hayes J.M.,National Hellenic Research Foundation | Leonidas D.D.,University of Thessaly
Mini-Reviews in Medicinal Chemistry | Year: 2010

Glycogen phosphorylase is an important therapeutic target for the potential treatment of type 2 diabetes. The importance of computation in the search for potent, selective and drug-like glycogen phosphorylase inhibitors which may eventually lead to antihyperglycemic drugs is now firmly established. Acting solo or more effectively in combination with experiment in a multidisciplinary approach to structure based drug design, current day modeling methods are an effective means of reducing the time and money spent on costly experimental procedures. Glycogen phosphorylase is an allosteric protein with five different ligand binding sites, hence offering multiple opportunities for modulation of enzyme activity. However, the binding sites have their own individual characteristics, so that different modeling approaches may be more effective for each. This review is focused on advances in the modeling and design of new inhibitors of the enzyme aimed towards providing the reader with some useful hints towards more successful computer-aided inhibitor (drug) design targeting glycogen phosphorylase. © 2010 Bentham Science Publishers Ltd.

Karousis N.,National Hellenic Research Foundation | Tagmatarchis N.,National Hellenic Research Foundation
Chemical Reviews | Year: 2010

The unique morphology and structure of carbon nanotubes (CNT) keep attracting a great number of researchers to explore the novel properties of these materials. Among various surface functionalization techniques, oxidation of CNTs is probably the most widely studied. Early treatment techniques involved gas-phase oxidation in air and oxidative plasmas. Carboxylated CNTs were extensively used as precursors for further covalent modification of CNTs, through esterification and/or amidation reactions. Moreover, a few other direct esterification/amidation procedures of oxidized CNTs were reported. In one of them, acid purified SWCNTs were treated with molten urea, which functions both as solvent and as reactant. Modification of CNTs with ionic liquids is expected to improve their compatibility and stability, enhancing the potential of CNTs in applications such as sensors and actuators, by improving the electrical contact with media.

Gonos E.S.,National Hellenic Research Foundation
Advances in Experimental Medicine and Biology | Year: 2010

Homeostasis is a key feature of cellular lifespan. Maintenance of cellular homeostasis influences the rate of aging and its efficiency is determined by the cooperation between protein stability and resistance to stress, protein refolding, protein repair and proteolysis of damaged proteins. Protein degradation is predominately catalyzed by the proteasome which isresponsible for cell clearance of abnormal, denatured or in general damaged proteins as well as for the regulated degradation of short-lived proteins. Impaired proteasome function has been tightly correlated to aging both in vivo and in vitro and thus, emphasis has been given recently in identifying ways of its activation. A number of studies have shown that the proteasome can be activated by genetic manipulations as well as by factors that affect either its conformation and tability or the expression of its subunits and the rate of proteasome assembly. This "readjustment" has been shown to have a great impact on retention of cellular homeostasis since it promotes lifespan extension. This chapter focuses on protein homeostasis and its direct link to proteasome function, dysfunction and manipulation and provides insights regarding the activation of proteasome-mediated protein degradation that, in turn, ensures health maintenance. ©2010 Landes Bioscience and Springer Science+Business Media.

Economopoulos S.P.,National Hellenic Research Foundation | Tagmatarchis N.,National Hellenic Research Foundation
Chemistry - A European Journal | Year: 2013

Graphene is turning out to be the material that will effectively kick-start a new era for nanotechnology. The impressive properties of this atom-thick carbon layer are taking shape and form with early reports of successful applications based on it. The turning point for this material will be its low-cost mass production. In this report a chemist's perspective on the production methods for graphene and the subsequent functionalization processes is discussed. The key for graphene's widespread adoption is its facile and cost-effective mass production. For material scientists, it is also important to chemically modify it, thus enriching its properties. A summary of the most widely-used exfoliation and covalent functionalization methods on the road from graphite flakes to graphene hybrid materials is presented (see figure). Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Pispas S.,National Hellenic Research Foundation
Soft Matter | Year: 2011

Vesicular structures composed of different components are attracting significant attention from the soft matter community both in terms of basic understanding of such complex assemblies of amphiphiles and in view of potential nanotechnological applications. In this article current developments in research concerning mixed vesicular structures assembled through interactions between synthetic block copolymers and low molecular weight surfactants are highlighted. Some future directions and perspectives for further advancement in the field are also discussed. © 2011 The Royal Society of Chemistry.

The self-assembled nanostructures formed in mixed solutions of a double hydrophilic anionic-neutral block copolymer, poly[(2-sulfamate-3-carboxylate) isoprene-b-ethylene oxide] (SCIEO), and the vesicle-forming surfactant, didodecyldimethylammonium bromide (DDAB), are investigated. In these solutions electrostatic interactions exist between the anionic poly[(2-sulfamate-3- carboxylate)isoprene] block and the cationic surfactant. Combined static and dynamic light scattering measurements indicate that at low copolymer concentration vesicles of DDAB with adsorbed block copolymer chains are present in the solutions. As block copolymer concentration increases the structure of the nanoassemblies transforms to a core-shell, micellar-like structure, with a poly(ethylene oxide) corona and a core formed by the complex of poly[(2-sulfamate-3-carboxylate)isoprene] chains and DDAB molecules. This transformation of global aggregate structure should be attributed to a collapse of the DDAB vesicle bilayer as the number of complexed surfactant head groups to anionic polymeric segments increases. This happens in order to satisfy the conformational requirements of the complexing polymeric block and the steric requirements in the PEO corona, which apparently overcome the existing interactions between surfactant molecules in the ordered bilayer of initial DDAB vesicles. Block copolymer decorated vesicles show lower stability to an increase in solution temperature compared to micellar-like aggregates. Both nanostructures are found to be stable to changes in solution ionic strength, due to the combination of electrostatic and hydrophobic interactions acting within the mixed aggregates. © 2011 The Royal Society of Chemistry.

Kyrtopoulos S.A.,National Hellenic Research Foundation
Environmental and Molecular Mutagenesis | Year: 2013

Although experience from the application of OMICS technologies in population-based environmental health studies is still relatively limited, the accumulated evidence shows that it can allow the identification of features (genes, proteins, and metabolites), or sets of such features, which are targeted by particular exposures or correlate with disease risk. Such features or profiles can therefore serve as biomarkers of exposure or disease risk. Blood-based OMIC profiles appear to reflect to some extent events occurring in target tissues and are associated with toxicity or disease and therefore have the potential to facilitate the elucidation of exposure-disease relationships. Further progress in this direction requires better understanding of the significance of exposure-induced network perturbations for disease initiation and progression and the development of a framework that combines agnostic searches with the utilization of prior knowledge, taking account of particular elements which characterize the structure and evolution of complex systems and brings in principles of systems biology. Environ. Mol. Mutagen. 54:468-479, 2013. © 2013 Wiley Periodicals, Inc.

Koufaki M.,National Hellenic Research Foundation
Expert Opinion on Therapeutic Patents | Year: 2014

Introduction: Lipoic acid (LA), a naturally occurring 1,2-dithiolane analog that plays an essential role in mitochondrial bioenergetic reactions, has gained unprecedented attention as nutritional supplement and as therapeutic agent. Moreover, LA conjugates with other pharmacophores represent a promising approach toward the development of multifunctional drugs. Areas covered: The reviewed patent applications from January 2011 to April 2014 include combinations of LA with other bioactive compounds as well as LA conjugates for the treatment of a wide range of clinical conditions. Additionally, some patents disclose methods to overcome the stability problems of LA. Expert opinion: LA is currently in clinical use for the treatment of diabetic neuropathy, while small clinical trials using combinations of LA with known bioactive agents have been undertaken. The use of the LA is hampered by its instability and its rapid metabolism. Thus, formulations containing LA, in a form ensuring its stability and improving its bioavailability, can have important applications as medicines, nutritional supplements or cosmeceuticals. LA hybrids with other pharmacophores endowed with various activities, possess an enormous potential to promote human health and have been the subject of numerous publications and patent applications. Nevertheless, reliable in vivo data and clinical trials are necessary to prove these beneficial effects. © 2014 Informa UK, Ltd.

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